The field used to represent mint production in Oregon is located in Marion County, in the Willamette Valley. According to the 1997 Census of Agriculture, Oregon is ranked 1st in peppermint production and 4th in spearmint production in the U.S. Marion County is among the top five in harvested acres in the state. Row spacing is from 20 to 30 inches and within row spacing is 4 to 6 inches. Plants spread by the second year to form a solid field of mint. Every 3 to 5 years, growers rotate the mint fields with another crop, generally perennial ryegrass or tall fescue in the Willamette Valley. Mint is mowed once or twice during the summer, depending on the variety. Plants require soils rich in organic matter with a pH range from 6.0 to 7.0. Water demand is high, therefore, irrigation is mandatory for a healthy crop. The soil selected to simulate the field is a Newberg fine sandy loam. Newberg fine sandy loam, is a coarse- loamy, mixed, superactive, mesic Fluventic Haploxerolls. The series is used to produce vegetable, fruit, and pasture. Mint is grown extensively on these soils. Newberg fine sandy loam is a very deep, somewhat excessively drained, moderately rapidly permeable soil with slow runoff. These soils formed in alluvium from sedimentary and basic igneous rocks. They are found on flood plains at elevations of 10 to 3,000 feet above mean sea level on slopes of 0 to 4 percent. The series are of moderate extent. Newberg fine sandy loam is a Hydrologic Group B soil.
|Starting Date||January 1, 1948||Meteorological File - Salem, OR (W24232)|
|Ending Date||December 31, 1983||Meteorological File - Salem, OR (W24232)|
|Pan Evaporation Factor (PFAC)||0.74||PRZM Manual Figure 5.1 (EPA, 1998)|
|Snowmelt Factor (SFAC)||0.15 cm C- 1||PRZM Manual Table 5.1 (EPA, 1998)|
|Minimum Depth of Evaporation (ANETD)||15.0 cm||PRZM Manual Figure 5.2 (EPA, 1998)|
|Method to Calculate Erosion (ERFLAG)||4 (MUSS)||PRZM Manual (EPA, 1998)|
|USLE K Factor (USLEK)||0.19 tons EI-1*||Farm Manual, Table 3.1 (EPA, 1985)|
|USLE LS Factor (USLELS)||0.69||Haan and Barfield, 1978|
|USLE P Factor (USLEP)||1.0||Set according to guidance (EPA, 2001)|
|Field Area (AFIELD)||172 ha||Area of Shipman Reservoir watershed (EPA, 1999)|
|NRCS Hyetograph (IREG)||2||PRZM Manual Figure 5.12 (EPA, 1998)|
|Slope (SLP)||4%||Value set to maximum for crop (EPA, 2001)|
|Hydraulic Length (HL)||600 m||Shipman Reservoir (EPA, 1999)|
* EI = 100 ft-tons * in/ acre*hr
|Initial Crop (INICRP)||1||Set to one for all crops (EPA, 2001)|
|Initial Surface Condition (ISCOND)||1||Set to reside prior to new crop planting; forest floor or meadow.|
|Number of Different Crops (NDC)||1||Set to crops in simulation - generally one|
|Number of Cropping Periods (NCPDS)||36||Set to weather data. Salem, OR (W24232)|
|Maximum rainfall interception storage of crop (CINTCP)||0.25||Set to default for orchards (EPA, 2001)|
|Maximum Active Root Depth (AMXDR)||30 cm||Gale Gingrich, Marion Co Ag Extension|
|Maximum Canopy Coverage (COVMAX)||100||Gale Gingrich, Marion Co Ag Extension|
|Soil Surface Condition After Harvest (ICNAH)||1||Orchards floor maintained similar to a meadow|
|Date of Crop Emergence
(EMD, EMM, IYREM)
|15/04||Gale Gingrich, Marion Co Ag Extension|
|Date of Crop Maturity
(MAD, MAM, IYRMAT)
|Date of Crop Harvest
(HAD, HAM, IYRHAR)
|Maximum Dry Weight (WFMAX)||0.0||Set to "0" Not used in simulation|
|SCS Curve Number (CN)||84, 79, 82||Gleams Manual Table A.3, meadow; condition good (USDA, 1990)|
|Manning's N Value (MNGN)||0.023||RUSLE Project, A19BSHLC, Medford barley rotated with hay; Salem OR (USDA, 2000)|
|USLE C Factor (USLEC)||0.019 - 0.381||RUSLE Project; A19BSHLC, Medford barley rotated with hay; Salem OR (USDA, 2000)|
|Total Soil Depth (CORED)||150 cm||NRCS, National Soils Characterization Database (NRCS, 2001)|
|Number of Horizons (NHORIZ)||4|
|First, Second, Third, and Fourth Soil Horizons (HORIZN = 1,2,3,4)|
|Horizon Thickness (THKNS)||
||NRCS, National Soils Characterization Database (NRCS, 2001) http://soils.usda.gov/survey/nscd/|
|Bulk Density (BD)||
|Initial Water Content (THETO)||
|Compartment Thickness (DPN)||
|Field Capacity (THEFC)||
|Wilting Point (THEWP)||
|Organic Carbon Content (OC)|
EPA. 1985. Field Agricultural Runoff Monitoring (FARM) Manual, (EPA/600/3-85/043) Environmental Research Laboratory, U.S. Environmental Protection Agency, Athens, GA.
EPA. 1998. Carsel, R.F., J.C. Imhoff, P.R. Hummel, J.M. Cheplick, and A.S. Donigian, Jr. PRZM-3, A Model for Predicting Pesticide and Nitrogen Fate in the Crop Root and Unsaturated Soil Zones: Users Manual for Release 3.0. National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Athens, GA.
EPA. 1999. Jones, R.D., J. Breithaupt, J. Carleton, L. Libelo, J. Lin, R. Matzner, and R. Parker. Guidance for Use of the Index Reservoir in Drinking Water Exposure Assessments. Environmental Fate and Effects Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington. D.C.
EPA. 2001. Abel, S.A. Procedure for Conducting Quality Assurance and Quality Control of Existing and New PRZM Field and Orchard Crop Standard Scenarios. Environmental Fate and Effects Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C.
Haan, C.T. and B.J. Barfield. 1978. Hydrology and Sedimentology of Surface Mined Lands. Office of Continuing Education and Extension, College of Engineering, University of Kentucky, Lexington, Kentucky 40506. pp. 286.
USDA. 1990. Davis, F.M., R.A. Leonard, W.G. Knisel. GLEAMS User Manual, Version 1.8.55. USDA-ARS Southeast Watershed Research Laboratory, Tifton GA. SEWRL-030190FMD.
USDA. 2000. Revised Universal Soil Loss Equation (RUSLE) EPA Pesticide Project. U.S. Department of Agriculture, National Resources Conservation Service (NRCS) and Agricultural Research Service (ARS).